3. A part or apart? “When you are saying that one thing belongs to another, you use a part,” writes Odyssey. “When you are saying that something is away from something else, you use apart. If you think about it, a part and apart are kind of opposites!”

4. Dash or hyphen? “When you’re setting off a clause—this one is a good example—use the longer dash, called an m-dash,” writes the Harvard College Writing Center. “You can indicate this dash with two hyphens—like this—if you don’t have an m-dash function on your computer. Be sure that the parts of the sentence that precede and follow the dashes would make sense even if you removed the dashes and the words they bracket. Whereas the m-dash is used to set off parts of a sentence, hyphens are used to join words together: ‘broken-hearted,’ ‘two-thirds,’ ‘sister-in-law.'”

5. Which or that? “The battle over whether to use which or that is one many people struggle to get right,” according to The Writer’s Dig. “It’s a popular grammar question and most folks want a quick rule of thumb so they can get it right. Here it is: If the sentence doesn’t need the clause that the word in question is connecting, use which. Examples: Our office, which has two lunchrooms, is located in Cincinnati. Our office that has two lunchrooms is located in Cincinnati.”

6. Lay or lie? “Lie and lay both have many definitions, but they’re most often confused where lie means to recline and lay means to put down,” writes Grammarist. “But the distinction is simple: Lay needs an object—something being laid—while lie cannot have an object. For example, you might lay a book on the table, lay a sweater on the bed, or lay a child in her crib. When you feel tired at the end of the day, you may lie down. But you can’t lie a book anywhere, and you can’t lay down (no object) at the end of the day.”

7. Who or whom? According to the Grammarly Blog, who should be used to refer to the subject of a sentence and whom should be used to refer to the object of a verb or preposition. “When in doubt, try this simple trick: If you can replace the word with ‘he’ or ‘she,’ use who. If you can replace it with ‘him’ or ‘her,’ use whom.”

8. Less or fewer? “If you want a simple rule, the difference between less and fewer is straightforward: The traditional advice is that fewer is for things you count, and less is for things you don’t count,” advises Grammar Girl. “You can count M&Ms, glasses of water, and potatoes—so you eat fewer M&Ms, serve fewer glasses of water, and buy fewer potatoes for the salad. You can’t count candy, water, or potato salad—so you eat less candy, observe that the lake has less water, and make less potato salad for the next potluck.”

9. Ensure or insure or assure? These three words are similar but have different meanings. Writing Explained suggests ways for remembering how to use each word correctly:

A good way to remember ensure is that it has two “e’s” in it, just like guarantee does. To ensure is to guarantee.

You can remember insure because it deals with finances and underwriting risks. You generally do this by taking out an insurance policy. Both words start with insur.

Assure is something that you tell to another person, something that can feel doubt or uncertainty. This means you only assure things that are alive. Both start with an A.